/* Test boundary conditions for $minDistance option for $near and $nearSphere
 * queries. SERVER-9395.
*/
var t = db.geo_mindistance_boundaries;
t.drop();
t.insert({loc: [1, 0]});  // 1 degree of longitude from origin.

/* $minDistance is supported for 2dsphere index only, not 2d or geoHaystack. */
t.ensureIndex({loc: "2dsphere"});

//
// Useful constants.
//

var km = 1000,
    earthRadiusMeters = 6378.1 * km,
    geoJSONPoint = {type: 'Point', coordinates: [0, 0]},
    // One degree of longitude at the equator, about 111 km.
    degreeInMeters = 2 * Math.PI * earthRadiusMeters / 360,
    metersEpsilon = Number.MIN_VALUE;

/* Grow epsilon's exponent until epsilon exceeds the margin of error for the
 * representation of degreeInMeters. The server uses 64-bit math, too, so we'll
 * find the smallest epsilon the server can detect.
*/
while (degreeInMeters + metersEpsilon == degreeInMeters) { metersEpsilon *= 2; }

//
// Test boundary conditions for $near and GeoJSON, in meters.
//


// minDistance must be within the args to $near, not on the side.
assert.throws(function() { t.find({loc:{$near:{$geometry: geoJSONPoint},
                                        $minDistance:0.1}}).itcount();});

assert.eq(
    1, t.find({loc: {
        $near: {$geometry: geoJSONPoint,
                $minDistance: degreeInMeters
    }}}).itcount(),
    "Expected to find (0, 1) within $minDistance 1 degree from origin"
);

assert.eq(
    1, t.find({loc: {
        $near: {$geometry: geoJSONPoint,
                $minDistance: degreeInMeters - metersEpsilon
    }}}).itcount(),
    "Expected to find (0, 1) within $minDistance (1 degree - epsilon) from origin"
);

assert.eq(
    0, t.find({loc: {
        $near: {$geometry: geoJSONPoint,
                $minDistance: degreeInMeters + metersEpsilon
    }}}).itcount(),
    "Expected *not* to find (0, 1) within $minDistance (1 degree + epsilon) from origin"
);

//
// Test boundary conditions for $nearSphere and GeoJSON, in meters.
//

assert.eq(
    1, t.find({loc: {
        $nearSphere: {$geometry: geoJSONPoint,
                      $minDistance: degreeInMeters
    }}}).itcount(),
    "Expected to find (0, 1) within $minDistance 1 degree from origin"
);

assert.eq(
    1, t.find({loc: {
        $nearSphere: geoJSONPoint,
        $minDistance: degreeInMeters - metersEpsilon
    }}).itcount(),
    "Expected to find (0, 1) within $minDistance (1 degree - epsilon) from origin"
);

assert.eq(
    0, t.find({loc: {
        $nearSphere: geoJSONPoint,
        $minDistance: degreeInMeters + metersEpsilon
    }}).itcount(),
    "Expected *not* to find (0, 1) within $minDistance (1 degree + epsilon) from origin"
);

//
// Test boundary conditions for $nearSphere and a legacy point, in radians.
//
// $minDistance with legacy point requires $nearSphere; $near not
// supported.
//

var legacyPoint = [0, 0],
    degreeInRadians = 2 * Math.PI / 360,
    radiansEpsilon = Number.MIN_VALUE;

while (1 + radiansEpsilon == 1) { radiansEpsilon *= 2; }

assert.eq(
    1, t.find({loc: {
        $nearSphere: legacyPoint,
        $minDistance: degreeInRadians
    }}).itcount(),
    "Expected to find (0, 1) within $minDistance 1 degree from origin"
);

assert.eq(
    1, t.find({loc: {
        $nearSphere: legacyPoint,
        $minDistance: degreeInRadians - radiansEpsilon
    }}).itcount(),
    "Expected to find (0, 1) within $minDistance (1 degree - epsilon) from origin"
);

assert.eq(
    0, t.find({loc: {
        $nearSphere: legacyPoint,
        $minDistance: degreeInRadians + radiansEpsilon
    }}).itcount(),
    "Expected *not* to find (0, 1) within $minDistance (1 degree + epsilon) from origin"
);
